The outskirts of spiral galaxies like our own could be crowded with colliding black holes of massive proportions and a prime location for scientists hunting the sources of gravitational waves, said researchers. Their study identifies an overlooked regi...

The outskirts of spiral galaxies like our own could be crowded with colliding black holes of massive proportions and a prime location for scientists hunting the sources of gravitational waves, said researchers. Their study identifies an overlooked region potentially rife with orbiting black holes. Identifying host galaxies of merging massive black holes could help explain how orbiting pairs of black holes form.